Improvement in cutting threads on pipes



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.IAMES'lVL CARPENTER, OF FLORENCE, .MASSACHUSETTS y Lette/rs Patent No.87,632, dated March 9, 1869.

IMPRovnMnNT 1N currrurnnnnns 'olv Pipes, ecc.

The Schedule referred to in these Letters Patentanf making parl: of thesama.

I`o all whom it may concern.

Be it known that I, J Aims M. CARPENTER, of Florence, in the county ofHampshire, and State of Massachusetts, have made and invented certainnew and usen ful Improvements in Machinery for Cutting Threads on Screwsand the like; and I do hereby declare that the following is a full,clear, and exact description of the construction andoperatiou of thesame, reference being had to' the annexed drawings, making apart 'ofthis specification, in which like letters mark like parts, and whereof-Figure 1 is an end, elevation, showing the segmental ,dies b b b",arranged on a single solid plate, a, such dies not being designed toopen for withdrawal of the screw after the thread on the same is cut;

Figure 2, a side orv edge elevation of the same;

Figure 3, an end elevation, showing the oscillating' ring i surroundingthe sliding head j, whereon are arranged the segmental dies g g g,designed to open for the withdrawal of the screw, after the threadthereon is cut;

Figure 4, a sideelevation oi'- the same, showing the bar m di Figure 5,a perspective view of a detached segmental er g Figure 6, anendelevation of ring i,

head j Figure 7, an end or face view of the sliding head j, whereon onesegmental die, g, is in cuttingposition, one, y, is 'open or thrownback, as for removal of a screw, and all other parts detached; f

Figure 8, an elevation of the opposite end of head j, all other partsbeing detached;

Figure 9, an end elevation of q and l Figure 10, an end elevation of theholds ring i in place.

My invention has for its object the more easy and perfect threading ofscrews, pipes, and the like; and

It consists in combining, with a head or holder, four pieces, more' orless, of metal, vhaving threads upon their inner ends, by means ofscrews or pivots, insuch mahner that they may be turned on their centresfor the purpose of obtaining an adjustment of theforward, orcutting-edges of the cutters, and alsoofeffecting, by the same movement,a clearance of the rear, or noncutting edges thereof.

detached from the stationaryl shell collar p, which l Heretofore sets'of cutters composing a die have been used, airangedto slideradially inways or grooves, for the purpose of opening the die, to release thescrew, and they are efficient for this purpose. -Theyhave also been madewith a curvature ofthe arc of a given circle, so that when sliddeninward radially, to act on a bolt, of a circumference less than thatcircle, they would give a proportionate clearance, which increased asthe cutter a proaclied the centre.

To enable ct ers skilled in the art to practise my l invention, idescribe the same as follows:

In the accompanying drawings, the part marked a represents a singlesolid plate, to which are attached, by pivot-screws o o o, the segmentaldies b bb, in the nature of equidistant radii, the outer ends of whichare secured and controlled by screws d d', or wedges o o', in`combination with the projections e e' which form a part of plate a.

Having thussecured blank dies in a proper position, I proceed to tap outthe same, and having previously made a continuous'stpaig'ht line, t,across the end and side of die and plate, that I may always determinethe exact position of each segment when tapped out,I then loosen screwsd or wedge o slightly, and tighten screw d or wedge fr correspondingly,thus moving the outer ends of dies b b l1" in the direction indicated byarrow 2, whereby it is obvious that the forward, or cutting-edge lr, ofeach segmental die, is moved toward the centre, y, of plate c, while therear, ornon-cutting cutting and non-cutting edges of the dies should bevery slight, i'or instance, the half oilia thousandth of an inch, orjust enough to obtain what I term a clearance, whereby the frictionincident to cutting screwthreads is greatly reduced:

If the threads in the dies become worn,` the edge o is easily sharpenedby grinding-'faces d d' 4", and then the cutting-edge fr may be advancedby turning the die-lever on its centre for the l.purpose of adjusting itto its former position.

Segment b" is designed to represent a holder, the inner end of which isprovided with a dovetail slot, wherein is arranged a removable die, c',and the die c may vary in length from pivot o, and in thickness ofthread thus aiordingthe means of cutting large or small screws by simplychanging the part 0.'.

My invention is designed to be used in connection with a Brown 8USharp77 screw-machine, or other similar machines, in which the blank,whereon a thread is to be cut, is made to revolve in a c chuck, whilethe thread-cutting dies have no revolving motion; but af# ter cutting athread by the above-described device, the screw must be removedtherefrom by a reverse motion of the chuck, which takes time, and ofteninjures or destroys the thread. And to obviate these objections, I havemade and invented an openingl-die or device, in which segmental diesg gg are" attached, by pivot 4screws o o o, to the sliding head j.

' Surrounding head j is an oscillating ring, i, provided withprojections e o', 86e., through which pass the screws d d', 86e.,whereby are held and controlled the outer ends of dies g g g", and thesedies, held fast on head j, are tapped out, as above described, and theirposition, when so tapped out, may always be determined by theline t',marked against the straight sides thereof, on the face of head j.

The ring i, .tting shank le, is held in proximity to head j by thecollar p, surrounding such shank, and whereon it is made fast by acommonfset-screwf edge s, recedes therefrom. But this variation of thethread. rection, bringing dies g g g again into cutting-posi;

g is a shell surrounding shank ic, and made fast in the screw-head, ,socalled, of a screw-machine.

the distance which ring 'i shall be allowed to oscillate..

h is a handle for operating ring i.

While a screw is being threaded, the blank is made to revolve in achuck, the thread.7 inthe die serving as a feed, and drawingthethread-cutting apparatus nearer such chlick, till the large screw Z,which rests on and slides along bar m, reaches notch n, when the ring iis oscillated in the direction indicated by arrow 1, whereby the dies gg' g are opened or thrown into position of die g', fig. 7, and the screwis then removed, without loss of time or injury o f Ring c' is nowoscillated in the opposite dition. Shank It is slid back into shell q,and the process repeated.

In forming. opening segmental dies g g', 85o., the thread-cutting partsthereof must be less than a semicircle, and made wholly on one side ofastraight line, passing through the centres of head j,- and anypivotscrew o otherwise, it is obvious, such dies could not be opened.

I prefer three segmental dies, as herein shown, but one, two, or more,may be used.

The tooth of the openingdies, or-that part b'e- Y tween the screws lfl', should be made curved on opposite sides, and the ends of suchscrews, a little rounded,

, in shown, I consider one and the same in principle, and

all equallyof my invention.

I am aware that screw-threaders, having al portion of their` inner endscut away, for clearance, have been swung on centres, and havebeenprovided with means fol-adjustment on such centres. Such a threader, Ido not claim; but having thus described the construction and operationof my improved device for cutting threads on screws and the like,

What I claim therein' as new, and desire to secure by'I-letters Patent,is

. 1. As my improvement of screw-threading dies, conjointly, theattachment of said dies, by pivots, to the die-stock, a series oflongitudinally-concave cuttingthreads, of equal height throughout theirentire length, and terminated at 'any angle to the curvature of saidthreads, in the plane of the straight-bevelled surface of the die-block,substantially as represented by iig. 4,

v and mechanism for adjusting said dies, to give clearance, and toretain them firmly in position when so adjusted, substantially as setforth.

2. Also, in combination with the dies, made and pivoted to thehead-stock, as described, the oscillating ring and the adjustingset-screws, or their' equivalent, the wedges, substantially asdescribed.

3. The notched arm m., in combina-tion with theshell q, ring i, and headj, substantially as and for the purpose described. y

JAMESM. CARPENTER.

Witnesses:

Rom. H. ALDRICH, A. PERRY PECK.

